Ophthalmic surgeons increasingly use new surgical methods and devices for changing the shape of a patient's cornea to correct vision defects, including myopia, hyperopia, and astigmatism. One such device is called a microkeratome which is used, in particular, to cut a corneal flap during performance of LASIK surgery. Unfortunately, there are problems with some of the microkeratomes used in corrective eye surgery.
More particularly, many microkeratomes suffer from one or more disadvantages including, for example, the inability of the microkeratome automatically to cut over a predetermined distance, the microkeratome being made of surgical steel which prevents the surgeon from viewing the cornea as the cutting blade advances, and/or the microkeratome being made of many small metal components which are expensive to produce and assemble. The largest dimension of some microkeratomes is less than about two inches (about five centimeters), meaning that individual components are even smaller. Reassembling such a microkeratome while wearing sterile gloves is particularly difficult. A microkeratome having many small components also is difficult, if not impossible, to clean and sterilize between patients.
Furthermore, some microkeratomes have exposed gears or screw threads which can become contaminated during the surgical operation. The small crevasses in these elements are particularly difficult to maintain in a sterile and smooth working condition. Furthermore, sterility problems have been reported in the field, making complete sterility of the components in the vicinity of the patient more important than ever. Additional problems with some existing microkeratomes are discussed in commonly owned U.S. Pat. No. 6,228,099, the entire disclosure of which is hereby incorporated herein by reference.
One of the better microkeratomes is disclosed in commonly owned International Application No. PCT/US98/24785, published as International Publication No. WO99/26568, which is hereby incorporated herein by reference in its entirety. Although the microkeratome disclosed therein is a significant improvement over microkeratomes at the time, further improvements are desirable.